YOU can imagine Steve Pemberton and the other writers of Whitechapel have a fine time coming up with scenarios to scare people silly.

For example: what could be more unnerving than being in the dentist’s chair when a serial killer turns up to perform some impromptu surgery?

In the first of a two-parter, Buchan is kidnapped and Miles taunted by an unknown force in the station, as Riley’s infected hand worsens. While Mansell teeters on the brink of self-destruction, Chandler heads the investigation into the discovery of a runner's disembowelled body in the sewers.

Could a mythical sow called the Black Swine and its offspring be at the root of the problem, or might a subterranean gang of cannibals be to blame?